Firing someone because of their gender identity is sex discrimination barred by Title VII of the Civil Rights Act of 1964.* Yesterday, Aimee Stephens, a transgender woman whose employer used religion as an excuse to fire her because she began dressing consistent with her gender identity, was in a federal appeals court fighting for her rights.

In E.E.O.C. v. Harris Funeral Homes, the Equal Employment Opportunity Commission, the independent federal agency that enforces the employment nondiscrimination protections in Title VII, sued Aimee’s employer on her behalf. The lower court granted the funeral home a free pass to use religion to justify violating Title VII under the Religious Freedom Restoration Act. That decision was a dangerous first—no other court has ever allowed a business to violate a civil-rights law for religious reasons.

Religious freedom gives us all the right to believe, or not, as we see fit. But it doesn’t give anyone the right to discriminate against others. And that’s just what Aimee’s lawyers said: The Establishment Clause of the First Amendment prohibits any religious exemption from a law if the exemption would harm other people. In other words, a business can’t fire an employee because its owner has a particular religious belief.

The case has profound implications for religious freedom. As we explained in our friend-of-the-court brief, if the lower court’s decision is upheld, “for-profit businesses would have broad—indeed, nearly limitless—license to engage in unlawful and invidious discrimination through a simple expedient: describing their discrimination as religiously based. Employers could prohibit employees from becoming pregnant out of wedlock, refuse to place women in managerial positions, or require employees to wear the symbols of the employer’s religion—and fire those who do not comply.”

Religious freedom is about fairness. It means we don’t treat people differently because their beliefs are different from ours. That’s discrimination, and that’s wrong. Being on the right side of history means being on the side of fairness and religious freedom.

*Today U.S. Attorney General Jeff Sessions issued a memorandum saying that he believes federal law doesn’t protect transgender workers from discrimination. This despite the fact that another federal agency, the E.E.O.C., represents Aimee in this case. And the fact that numerous federal courts across the country have clearly said that Title VII’s bar on sex discrimination includes discrimination based on gender identity and protects transgender employees. Sessions’ memo is just wrong.